FORT BRAGG, N.C. — In the crowded hangar at Simmons Army Airfield, Aaron Williams is saying goodbye to his family. Again.

It’s his third deployment to war, and the first since 8-month-old Derek was born.

“I’m getting out after this one,” he says, as his son, Tristan, 2, energetically waves the small flags he’s holding tightly in each hand. “It’s too hard on the kids, too hard for me.”

For the members of the 82nd Airborne’s Combat Aviation Brigade, three war tours in the past five years is not uncommon. On this hot and sticky September day at Fort Bragg, about 200 members of the brigade got their final medical checks, hoisted rucksacks and squeezed in their final farewell hugs with few outward signs of the strain wrought by the long and repeated deployments.

Army aviators — the soldiers who fly attack missions, ferry troops and supplies, and evacuate the wounded — are in ever-increasing demand even as America eyes the exits in Afghanistan. The Afghanistan conflict, which marked its 10th anniversary Friday, is in many ways a helicopter war.

“This war is so helicopter-centric,” said Col. T.J. Jamison, the brigade commander. “We’re just limited in the number of helicopters we have. And, they are absolutely needed. You can’t get enough aviation into Afghanistan right now.”

The pilots are flying roughly 63 hours a month, nearly five times the peacetime average, and often through rugged Afghan mountain terrain in the pitch-black night.

Top Army leaders are well aware of the combat demands on their aviation brigades — war requirements that have forced long and repeated tours to Iraq and Afghanistan. And they know that as the Pentagon works to extend the time soldiers spend at home between deployments, the aviation units will be among the last to see the longer breaks.

According to Army officials, their flight crews have flown more than 1.2 million hours in Afghanistan as of mid-August, and triple that number in Iraq. The bulk of those are in Black Hawk and Apache helicopters.

To meet the war demands, the Army increased the number of aviation brigades, and now has 12 active duty and eight National Guard units. A 13th active duty brigade will be ready next year.

The grueling deployment pace is a key contributor to the devastating mental and emotional toll the wars are taking on America’s military people. The suicide rate has escalated across the services, along with incidents of post-traumatic stress disorder and traumatic brain injuries.

Officials estimate that as many as a fifth of the active duty troops has suffered acute stress, anxiety, depression or other mental problems from a war zone deployment. But many don’t seek help, and commanders struggle to monitor their troops and recognize any early signs of distress.

Still, it’s difficult to predict who might be affected, or when.

Maj. Stanton Trotter, the aviation brigade’s chaplain, is moving through the hangar talking with soldiers and their families. He’ll go to these goodbye ceremonies until all 2,500 members have deployed.

On this day, there are the wide-eyed, eager first-timers among the soldiers boarding buses that will take them on the first leg of a nearly weeklong journey to Afghanistan. There are also a lot of veterans who can tick off the dates of their multiple deployments, punctuated by asides on whether they were home or away for holidays or when their children were born.

When Lt. Col. John Cyrulik was figuring out the leave schedule for his Task Force Wolfpack battalion over the next year, he gave priority to those who had the most months at war since 2006.

“We have over a dozen that have been deployed nearly three years of the past five,” said Col. Cyrulik. Others, he said, have seen as many as 30 months at war since 2006.